nitazoxanide

Nitazoxanide is an antiparasitic and antiviral medication used orally (suspension or tablets). It is a thiazolide prodrug that is rapidly deacetylated to the active metabolite tizoxanide. It has activity against protozoa such as Giardia lamblia, Entamoeba histolytica, and Cryptosporidium parvum, and against some helminths; it has also shown antiviral effects against rotavirus and influenza and has been investigated for SARS-CoV-2.

The primary mechanism is inhibition of the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer, disrupting anaerobic energy metabolism in susceptible organisms. The antiviral mechanisms are not fully understood and may involve modulation of host pathways required for viral replication.

Clinical use: nitazoxanide is approved for treatment of diarrhea caused by Giardia lamblia and Cryptosporidium parvum in adults and children. It is sometimes used off-label for other protozoal infections and has been studied for various viral infections, though antiviral approvals vary by jurisdiction.

Administration: oral, available as suspension and tablets. In children, typical dosing is 7.5 mg/kg per dose every 12 hours for 3 days; in adults, commonly 500 mg twice daily for 3 days. Dosing should follow local labeling and clinician guidance.

Safety and regulatory status: generally well tolerated; common adverse effects include abdominal pain, nausea, vomiting, and stool changes. Safety in pregnancy and liver impairment is not fully established; use should follow clinical advice. Brand names include Alinia in some markets; listed in WHO essential medicines lists for certain pediatric diarrheal diseases.